I did a little video lesson of how you can use a diminished arpeggio/scale to connect the I and the IV in a blues progression. Let me know what you think. It would probably be better to have a closeup shot of the neck. I'll do more of these, and next time, I'll position the camera up close on the neck.

http://www.dolphinstreet.com/guitar_video_lessons
(First lesson in list.)